Credits: Science Museum

This was intended to be sold only as an ingredient for chemists making up prescriptions – if otherwise sold, the label suggests that the seller could be “liable to a penalty”. This is possibly because such extracts from the Damiana herb had been taken in South America since ancient times for their supposed aphrodisiac qualities. Here, the manufacturers C J Hewlett’s & Son suggest it can be used as a constituent of a mixture used to treat “nervous exhaustion”, “chronic alcoholism” and what they describe as “Brain fag” – a phrase once used to describe mental fatigue.